Does the below 2 syntaxes are same,
moment(1456261200367, 'H:mm:ss.SSS').utc().valueOf() //1456343786120
moment(1456261200367 +0000, 'H:mm:ss.SSS Z').valueOf() //1456325786120
but as you could see if both of them coverts the given value to UTC mode then why there is a difference in the output?
Also I would like to know how a.valueOf() and b.valueOf() are same, when a.format() and b.format() are different, because moment() (moment parses and displays in local time) is different from moment.utc() (displays a moment in UTC mode)
var a = moment();
var b = moment.utc();
a.format();
b.format();
a.valueOf();
b.valueOf();
In the first part, you're using it incorrectly. You've passed numeric input which would normally be interpreted as a unix timestamp, but then you've supplied a string-based format string so the number is converted to a string. The format string here is telling moment how the input is specified, but it doesn't match what you're actually parsing.
This doesn't error though, because by default moment's parser is in "forgiving" mode. You can read more about this in the docs.
The correct way to pass a timestamp into moment is with one of these:
moment(1456261200367)
moment(1456261200367).utc()
moment.utc(1456261200367)
The last two are equivalent, but the moment.utc(timestamp) form is prefered.
With any of those, all three will have the same .valueOf(), which is just the timestamp you started with. The difference is in the mode that the moment object is in. The first one is in local mode, reflecting the time zone of the computer where it's running, while the other two are in UTC mode.
This is evident when you format the output using the format function, as with other many other functions. I believe that answers your second question as well.
Related
I am just printing the ISO datetime with timezone as per the below documentation
http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a003169814.htm
This is my code
TimeZone tz = TimeZone.getTimeZone("UTC");
DateFormat df = new SimpleDateFormat("yyyy-mm-dd'T'hh:mm:ss.nnnnnn+|-hh:mm");
df.setTimeZone(tz);
dateTimeWithTimeZone = df.format(new Date());
However i am getting this exception
Illegal pattern character 'n'
I cant use this format directly in Java ?
java.time
dateTimeWithTimeZone = Instant.now().toString();
System.out.println(dateTimeWithTimeZone);
When I ran this snippet just now, I got this output:
2019-03-18T22:28:13.549319Z
It’s not clear from the page you link to, but it’s an ISO 8601 string in UTC, so should be all that you need. I am taking advantage of the fact that the classes of java.time produce ISO 8601 output from their toString methods. The linked page does show the format with hyphens, T and colons (2008-09-15T15:53:00+05:00), it shows another example with decimals on the seconds (15:53:00.322348) and a third one with Z meaning UTC (20080915T155300Z), so I would expect that the combination of all three of these would be OK too.
The format you used in the quesiton seems to try to get the offset as +00:00 rather than Z. If this is a requirement, it’s only a little bit more complicated. We are using an explicit formatter to control the variations within ISO 8601:
DateTimeFormatter iso8601Formatter
= DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ss.SSSSSSxxx");
dateTimeWithTimeZone = OffsetDateTime.now(ZoneOffset.UTC).format(iso8601Formatter);
System.out.println(dateTimeWithTimeZone);
2019-03-18T22:28:13.729711+00:00
What went wrong in your code?
You tried to use the formatting symbols from your source with SimpleDateFormat. First, you should never, and especially not in Java 8 or later, want to use SimpleDateFormat. That class is notoriously troublesome and long outdated. Second, some of its format pattern letters agree with the symbols from your source, some of them don’t, so you cannot just use the symvol string from there. Instead you need to read the documentation and find the correct format pattern letters to use for year, month, etc. And be aware that they are case sensitive: MM and mm are different.
Link
Oracle Tutorial: Date Time
explaining how to use java.time.
I've found a couple of existing StackoverFlow questions on this but nothing very definite.
I have a local datetime. I want this in UTC. my local datetime does not have a 'Z' at the end or any offset information.
I first tried:
moment(mylocaldatetime).toISOString() #works fine because this method always returns time in UTC
But for consistency with other code I didn't want to use to ISOString() so I did this:
moment(mylocaldatetime).utc().format()
This seems to work fine. If the browser running this code is in UTC + 1 I get a datetime one hour less than mylocaldatetime (with an offset string if I specify that in the format). I.e. it has treated mylocaldatetime as a local time, taken account of my current time zone, and given me my local time as UTC.
However. This appears to contradict the moment.js docs which are pretty clear that:
If you want to parse or display a moment in UTC, you can use moment.utc() instead of moment(). - Notice the 'parse'.
and
Moment normally interprets input times as local times (or UTC times if moment.utc() is used).
If these doc comments were true this line:
moment(mylocaldatetime).utc().format()
should treat mylocaldatetime as if it were utc and then output this datetime in utc - no difference. No conversion. But that is not what I get.
Maybe what this line moment(mylocaldatetime).utc().format() is saying is:
create a moment object in local mode with mylocaldatetime. Then put the moment object into utc mode. So now when we format for display we output as utc. IF this is the case I think the docs could be made clearer.
I am wondering what this does:
newM = moment("2015-08-11T13:00:00.000000Z", "YYYY-MM-DDTHH:mm:ss.SSSS[Z]", true)
Specifically - the [Z] in the format string.
I am using a library (react-bootstrap-datetimepicker) which uses moment. This library (React component) takes a parameter 'format' which is used as the second parameter to moment
I can't see what the [Z] is doing. But I have to do this rather than just 'Z' to get the result I want when I format the moment object for display with this string: newM.format('YYYY-MM-DD HH:mm:ss.SSSZ').
EDIT:
to be clear: I understand that 'Z' will cause the datetime passed to be treated as UTC, as per the docs. But what is the significance of the square brackets - which are not in the docs.
For everyone who cares about consistency due to the missing Z at the end - try to add [Z] to your format.
Example: .format('YYYY-MM-DDTHH:mm:ss[Z]') so the result is: 2019-11-26T10:39:54Z
More detailed explanation you can find in this github issue.
Z does not cause the time to be treated as UTC when used in the format. It matches a timezone specifier:
Format: Z ZZ
Example: +12:00
Description: Offset from UTC as +-HH:mm, +-HHmm, or Z
And under the documentation for format:
To escape characters in format strings, you can wrap the characters in
square brackets.
By specifying Z in brackets, you are matching a literal Z, and thus the timezone is left at moment's default, which is the local timezone.
Unless you specify a time zone offset, parsing a string will create a
date in the current time zone.
If your time is really in UTC, this is probably not desired behavior. If you want to parse it as UTC but display it in local time, use Z and then call local() on the resulting moment object, so most likely what you want is:
// Parse with timezone specifier (which is UTC here) but convert to local time
newM = moment("2015-08-11T13:00:00.000000Z", "YYYY-MM-DDTHH:mm:ss.SSSSZ", true).local();
I've read thru various posts on here in regards to similiar issues but none have solved my problem.
I manipulate the moment.js date object, and then store it as timestamp.
BUT, when I try to read in that timestamp again, I get that deprecated warning.
""Deprecation warning: moment construction falls back to js Date. This is discouraged and will be removed in upcoming major release. Please refer to https://github.com/moment/moment/issues/1407 for more info."
I've tried toDate(), format(), moment(myTimeStamp, 'ddd, DD MMM YYYY HH:mm:ss ZZ'); --> all generate the warning...
So, for example, my timestamp will look like this:
const timestamp = '1458586740000'
when I read that back and try to parse out the month/day/year, then the hour/min am/pm, etc... I need to get that timestamp into a moment.js object. Nothing is working for me. Any ideas.
How can I get this timestamp: '1458586740000', into a moment.js object so I can extract date date from it as I need?
EDIT: this is how I am storing the timestamp. So I would need to retrieve it from this.
let timeStamp = Moment(state[_Date])
.add({ hour: state[AMPM] === 'PM'
? +state[Hour] + 12
: state[Hour] ,
minute: state[Min] }).format('x')
The X token indicates a unix timestamp in seconds, and the x token indicates a unix millisecond timestamp (offset).
You appear to have a millisecond timestamp, so you would make a moment out of it by doing the following:
var a = moment('1458586740000', 'x')
It works without ' as well:
var a = moment(1458586740000, 'x')
You can also not specify the x and it should work:
moment(1458586740000)
Because you have a unix offset (milliseconds), not a unix timestamp (seconds), moment.unix is not what you want.
Then you can do the following:
a.format()
"2016-03-21T13:59:00-05:00"
Or you can use any of the other formatting tokens listed here to output whatever result you would like: http://momentjs.com/docs/#/displaying/format/
Based on the code you presented, I think you may be having problems because your timestamp is stored as a string (in ''). Parsing as a string causes an invalid date error, because it attempts to match ISO 8601 format and fails. Specifying that 'x' token will cause it to assume unix offset and work correctly.
On a 32 bit OS, with an Intel processor,
DateTime e.g. 2/17/2009 12:00:00 AM
Notice that it is: mm/DD//yyyy
On a 64 bit OS, with an AMD processor,
DateTime e.g. 17-02-2009 00:00:00
Now when I try to parse the 1st format, it throws an error on the 2nd platform.
That means - DateTime.Parse("2/17/2009 12:00:00 AM") - throws an error - cannot convert.
whereas, on the same platform,
DateTime.Parse("17/2/2009 12:00:00 AM") works! That means DD/MM is fine, MM/DD is not.
What is causing this? The 64-bit OS? The processor?
How do I get rid of the problem?
DateTimes themselves don't have formats. You parse them or format them into strings. (It's like numbers - integers aren't stored in hex or decimal, they're just integers. You can format them in hex or decimal, but the value itself is just a number.)
The format will depend on the culture of the operating system (or more accurately, the culture of the thread, which is typically the same as the operating system one).
Personally I like to explicitly set the format I use for either parsing or formatting, unless I'm actually displaying the string to the user and know that the culture is appropriate already.
Check your "Date and time formats" in the "Region and Language" control panel.
Also, if you want DateTime to generate a specific format, don't just call plain ToString(), but pass it a parameter indicating the format you want. Similarly, if you know the format of the date you are asking it to parse, call TryParseExact(), and tell it the format you are providing.
See also MSDN's Standard Date and Time Format Strings